events.rs

   1use std::rc::Rc;
   2
   3use ::util::ResultExt;
   4use anyhow::Context as _;
   5use windows::{
   6    Win32::{
   7        Foundation::*,
   8        Graphics::Gdi::*,
   9        System::SystemServices::*,
  10        UI::{
  11            Controls::*,
  12            HiDpi::*,
  13            Input::{Ime::*, KeyboardAndMouse::*},
  14            WindowsAndMessaging::*,
  15        },
  16    },
  17    core::PCWSTR,
  18};
  19
  20use crate::*;
  21
  22pub(crate) const WM_GPUI_CURSOR_STYLE_CHANGED: u32 = WM_USER + 1;
  23pub(crate) const WM_GPUI_CLOSE_ONE_WINDOW: u32 = WM_USER + 2;
  24pub(crate) const WM_GPUI_TASK_DISPATCHED_ON_MAIN_THREAD: u32 = WM_USER + 3;
  25pub(crate) const WM_GPUI_DOCK_MENU_ACTION: u32 = WM_USER + 4;
  26pub(crate) const WM_GPUI_FORCE_UPDATE_WINDOW: u32 = WM_USER + 5;
  27pub(crate) const WM_GPUI_KEYBOARD_LAYOUT_CHANGED: u32 = WM_USER + 6;
  28pub(crate) const WM_GPUI_GPU_DEVICE_LOST: u32 = WM_USER + 7;
  29pub(crate) const WM_GPUI_KEYDOWN: u32 = WM_USER + 8;
  30
  31const SIZE_MOVE_LOOP_TIMER_ID: usize = 1;
  32const AUTO_HIDE_TASKBAR_THICKNESS_PX: i32 = 1;
  33
  34impl WindowsWindowInner {
  35    pub(crate) fn handle_msg(
  36        self: &Rc<Self>,
  37        handle: HWND,
  38        msg: u32,
  39        wparam: WPARAM,
  40        lparam: LPARAM,
  41    ) -> LRESULT {
  42        let handled = match msg {
  43            WM_ACTIVATE => self.handle_activate_msg(wparam),
  44            WM_CREATE => self.handle_create_msg(handle),
  45            WM_MOVE => self.handle_move_msg(handle, lparam),
  46            WM_SIZE => self.handle_size_msg(wparam, lparam),
  47            WM_GETMINMAXINFO => self.handle_get_min_max_info_msg(lparam),
  48            WM_ENTERSIZEMOVE | WM_ENTERMENULOOP => self.handle_size_move_loop(handle),
  49            WM_EXITSIZEMOVE | WM_EXITMENULOOP => self.handle_size_move_loop_exit(handle),
  50            WM_TIMER => self.handle_timer_msg(handle, wparam),
  51            WM_NCCALCSIZE => self.handle_calc_client_size(handle, wparam, lparam),
  52            WM_DPICHANGED => self.handle_dpi_changed_msg(handle, wparam, lparam),
  53            WM_DISPLAYCHANGE => self.handle_display_change_msg(handle),
  54            WM_NCHITTEST => self.handle_hit_test_msg(handle, msg, wparam, lparam),
  55            WM_PAINT => self.handle_paint_msg(handle),
  56            WM_CLOSE => self.handle_close_msg(),
  57            WM_DESTROY => self.handle_destroy_msg(handle),
  58            WM_MOUSEMOVE => self.handle_mouse_move_msg(handle, lparam, wparam),
  59            WM_MOUSELEAVE | WM_NCMOUSELEAVE => self.handle_mouse_leave_msg(),
  60            WM_NCMOUSEMOVE => self.handle_nc_mouse_move_msg(handle, lparam),
  61            // Treat double click as a second single click, since we track the double clicks ourselves.
  62            // If you don't interact with any elements, this will fall through to the windows default
  63            // behavior of toggling whether the window is maximized.
  64            WM_NCLBUTTONDBLCLK | WM_NCLBUTTONDOWN => {
  65                self.handle_nc_mouse_down_msg(handle, MouseButton::Left, wparam, lparam)
  66            }
  67            WM_NCRBUTTONDOWN => {
  68                self.handle_nc_mouse_down_msg(handle, MouseButton::Right, wparam, lparam)
  69            }
  70            WM_NCMBUTTONDOWN => {
  71                self.handle_nc_mouse_down_msg(handle, MouseButton::Middle, wparam, lparam)
  72            }
  73            WM_NCLBUTTONUP => {
  74                self.handle_nc_mouse_up_msg(handle, MouseButton::Left, wparam, lparam)
  75            }
  76            WM_NCRBUTTONUP => {
  77                self.handle_nc_mouse_up_msg(handle, MouseButton::Right, wparam, lparam)
  78            }
  79            WM_NCMBUTTONUP => {
  80                self.handle_nc_mouse_up_msg(handle, MouseButton::Middle, wparam, lparam)
  81            }
  82            WM_LBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Left, lparam),
  83            WM_RBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Right, lparam),
  84            WM_MBUTTONDOWN => self.handle_mouse_down_msg(handle, MouseButton::Middle, lparam),
  85            WM_XBUTTONDOWN => {
  86                self.handle_xbutton_msg(handle, wparam, lparam, Self::handle_mouse_down_msg)
  87            }
  88            WM_LBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Left, lparam),
  89            WM_RBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Right, lparam),
  90            WM_MBUTTONUP => self.handle_mouse_up_msg(handle, MouseButton::Middle, lparam),
  91            WM_XBUTTONUP => {
  92                self.handle_xbutton_msg(handle, wparam, lparam, Self::handle_mouse_up_msg)
  93            }
  94            WM_MOUSEWHEEL => self.handle_mouse_wheel_msg(handle, wparam, lparam),
  95            WM_MOUSEHWHEEL => self.handle_mouse_horizontal_wheel_msg(handle, wparam, lparam),
  96            WM_SYSKEYUP => self.handle_syskeyup_msg(wparam, lparam),
  97            WM_KEYUP => self.handle_keyup_msg(wparam, lparam),
  98            WM_GPUI_KEYDOWN => self.handle_keydown_msg(wparam, lparam),
  99            WM_CHAR => self.handle_char_msg(wparam),
 100            WM_IME_STARTCOMPOSITION => self.handle_ime_position(handle),
 101            WM_IME_COMPOSITION => self.handle_ime_composition(handle, lparam),
 102            WM_SETCURSOR => self.handle_set_cursor(handle, lparam),
 103            WM_SETTINGCHANGE => self.handle_system_settings_changed(handle, wparam, lparam),
 104            WM_INPUTLANGCHANGE => self.handle_input_language_changed(),
 105            WM_SHOWWINDOW => self.handle_window_visibility_changed(handle, wparam),
 106            WM_GPUI_CURSOR_STYLE_CHANGED => self.handle_cursor_changed(lparam),
 107            WM_GPUI_FORCE_UPDATE_WINDOW => self.draw_window(handle, true),
 108            WM_GPUI_GPU_DEVICE_LOST => self.handle_device_lost(lparam),
 109            _ => None,
 110        };
 111        if let Some(n) = handled {
 112            LRESULT(n)
 113        } else {
 114            unsafe { DefWindowProcW(handle, msg, wparam, lparam) }
 115        }
 116    }
 117
 118    fn handle_move_msg(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 119        let mut lock = self.state.borrow_mut();
 120        let origin = logical_point(
 121            lparam.signed_loword() as f32,
 122            lparam.signed_hiword() as f32,
 123            lock.scale_factor,
 124        );
 125        lock.origin = origin;
 126        let size = lock.logical_size;
 127        let center_x = origin.x.0 + size.width.0 / 2.;
 128        let center_y = origin.y.0 + size.height.0 / 2.;
 129        let monitor_bounds = lock.display.bounds();
 130        if center_x < monitor_bounds.left().0
 131            || center_x > monitor_bounds.right().0
 132            || center_y < monitor_bounds.top().0
 133            || center_y > monitor_bounds.bottom().0
 134        {
 135            // center of the window may have moved to another monitor
 136            let monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 137            // minimize the window can trigger this event too, in this case,
 138            // monitor is invalid, we do nothing.
 139            if !monitor.is_invalid() && lock.display.handle != monitor {
 140                // we will get the same monitor if we only have one
 141                lock.display = WindowsDisplay::new_with_handle(monitor);
 142            }
 143        }
 144        if let Some(mut callback) = lock.callbacks.moved.take() {
 145            drop(lock);
 146            callback();
 147            self.state.borrow_mut().callbacks.moved = Some(callback);
 148        }
 149        Some(0)
 150    }
 151
 152    fn handle_get_min_max_info_msg(&self, lparam: LPARAM) -> Option<isize> {
 153        let lock = self.state.borrow();
 154        let min_size = lock.min_size?;
 155        let scale_factor = lock.scale_factor;
 156        let boarder_offset = lock.border_offset;
 157        drop(lock);
 158        unsafe {
 159            let minmax_info = &mut *(lparam.0 as *mut MINMAXINFO);
 160            minmax_info.ptMinTrackSize.x =
 161                min_size.width.scale(scale_factor).0 as i32 + boarder_offset.width_offset;
 162            minmax_info.ptMinTrackSize.y =
 163                min_size.height.scale(scale_factor).0 as i32 + boarder_offset.height_offset;
 164        }
 165        Some(0)
 166    }
 167
 168    fn handle_size_msg(&self, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 169        let mut lock = self.state.borrow_mut();
 170
 171        // Don't resize the renderer when the window is minimized, but record that it was minimized so
 172        // that on restore the swap chain can be recreated via `update_drawable_size_even_if_unchanged`.
 173        if wparam.0 == SIZE_MINIMIZED as usize {
 174            lock.restore_from_minimized = lock.callbacks.request_frame.take();
 175            return Some(0);
 176        }
 177
 178        let width = lparam.loword().max(1) as i32;
 179        let height = lparam.hiword().max(1) as i32;
 180        let new_size = size(DevicePixels(width), DevicePixels(height));
 181
 182        let scale_factor = lock.scale_factor;
 183        let mut should_resize_renderer = false;
 184        if lock.restore_from_minimized.is_some() {
 185            lock.callbacks.request_frame = lock.restore_from_minimized.take();
 186        } else {
 187            should_resize_renderer = true;
 188        }
 189        drop(lock);
 190
 191        self.handle_size_change(new_size, scale_factor, should_resize_renderer);
 192        Some(0)
 193    }
 194
 195    fn handle_size_change(
 196        &self,
 197        device_size: Size<DevicePixels>,
 198        scale_factor: f32,
 199        should_resize_renderer: bool,
 200    ) {
 201        let new_logical_size = device_size.to_pixels(scale_factor);
 202        let mut lock = self.state.borrow_mut();
 203        lock.logical_size = new_logical_size;
 204        if should_resize_renderer {
 205            lock.renderer.resize(device_size).log_err();
 206        }
 207        if let Some(mut callback) = lock.callbacks.resize.take() {
 208            drop(lock);
 209            callback(new_logical_size, scale_factor);
 210            self.state.borrow_mut().callbacks.resize = Some(callback);
 211        }
 212    }
 213
 214    fn handle_size_move_loop(&self, handle: HWND) -> Option<isize> {
 215        unsafe {
 216            let ret = SetTimer(
 217                Some(handle),
 218                SIZE_MOVE_LOOP_TIMER_ID,
 219                USER_TIMER_MINIMUM,
 220                None,
 221            );
 222            if ret == 0 {
 223                log::error!(
 224                    "unable to create timer: {}",
 225                    std::io::Error::last_os_error()
 226                );
 227            }
 228        }
 229        None
 230    }
 231
 232    fn handle_size_move_loop_exit(&self, handle: HWND) -> Option<isize> {
 233        unsafe {
 234            KillTimer(Some(handle), SIZE_MOVE_LOOP_TIMER_ID).log_err();
 235        }
 236        None
 237    }
 238
 239    fn handle_timer_msg(&self, handle: HWND, wparam: WPARAM) -> Option<isize> {
 240        if wparam.0 == SIZE_MOVE_LOOP_TIMER_ID {
 241            for runnable in self.main_receiver.drain() {
 242                runnable.run();
 243            }
 244            self.handle_paint_msg(handle)
 245        } else {
 246            None
 247        }
 248    }
 249
 250    fn handle_paint_msg(&self, handle: HWND) -> Option<isize> {
 251        self.draw_window(handle, false)
 252    }
 253
 254    fn handle_close_msg(&self) -> Option<isize> {
 255        let mut callback = self.state.borrow_mut().callbacks.should_close.take()?;
 256        let should_close = callback();
 257        self.state.borrow_mut().callbacks.should_close = Some(callback);
 258        if should_close { None } else { Some(0) }
 259    }
 260
 261    fn handle_destroy_msg(&self, handle: HWND) -> Option<isize> {
 262        let callback = {
 263            let mut lock = self.state.borrow_mut();
 264            lock.callbacks.close.take()
 265        };
 266        if let Some(callback) = callback {
 267            callback();
 268        }
 269        unsafe {
 270            PostMessageW(
 271                Some(self.platform_window_handle),
 272                WM_GPUI_CLOSE_ONE_WINDOW,
 273                WPARAM(self.validation_number),
 274                LPARAM(handle.0 as isize),
 275            )
 276            .log_err();
 277        }
 278        Some(0)
 279    }
 280
 281    fn handle_mouse_move_msg(&self, handle: HWND, lparam: LPARAM, wparam: WPARAM) -> Option<isize> {
 282        self.start_tracking_mouse(handle, TME_LEAVE);
 283
 284        let mut lock = self.state.borrow_mut();
 285        let Some(mut func) = lock.callbacks.input.take() else {
 286            return Some(1);
 287        };
 288        let scale_factor = lock.scale_factor;
 289        drop(lock);
 290
 291        let pressed_button = match MODIFIERKEYS_FLAGS(wparam.loword() as u32) {
 292            flags if flags.contains(MK_LBUTTON) => Some(MouseButton::Left),
 293            flags if flags.contains(MK_RBUTTON) => Some(MouseButton::Right),
 294            flags if flags.contains(MK_MBUTTON) => Some(MouseButton::Middle),
 295            flags if flags.contains(MK_XBUTTON1) => {
 296                Some(MouseButton::Navigate(NavigationDirection::Back))
 297            }
 298            flags if flags.contains(MK_XBUTTON2) => {
 299                Some(MouseButton::Navigate(NavigationDirection::Forward))
 300            }
 301            _ => None,
 302        };
 303        let x = lparam.signed_loword() as f32;
 304        let y = lparam.signed_hiword() as f32;
 305        let input = PlatformInput::MouseMove(MouseMoveEvent {
 306            position: logical_point(x, y, scale_factor),
 307            pressed_button,
 308            modifiers: current_modifiers(),
 309        });
 310        let handled = !func(input).propagate;
 311        self.state.borrow_mut().callbacks.input = Some(func);
 312
 313        if handled { Some(0) } else { Some(1) }
 314    }
 315
 316    fn handle_mouse_leave_msg(&self) -> Option<isize> {
 317        let mut lock = self.state.borrow_mut();
 318        lock.hovered = false;
 319        if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
 320            drop(lock);
 321            callback(false);
 322            self.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
 323        }
 324
 325        Some(0)
 326    }
 327
 328    fn handle_syskeyup_msg(&self, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 329        let mut lock = self.state.borrow_mut();
 330        let input = handle_key_event(wparam, lparam, &mut lock, |keystroke, _| {
 331            PlatformInput::KeyUp(KeyUpEvent { keystroke })
 332        })?;
 333        let mut func = lock.callbacks.input.take()?;
 334        drop(lock);
 335        func(input);
 336        self.state.borrow_mut().callbacks.input = Some(func);
 337
 338        // Always return 0 to indicate that the message was handled, so we could properly handle `ModifiersChanged` event.
 339        Some(0)
 340    }
 341
 342    // It's a known bug that you can't trigger `ctrl-shift-0`. See:
 343    // https://superuser.com/questions/1455762/ctrl-shift-number-key-combination-has-stopped-working-for-a-few-numbers
 344    fn handle_keydown_msg(&self, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 345        let mut lock = self.state.borrow_mut();
 346        let Some(input) = handle_key_event(
 347            wparam,
 348            lparam,
 349            &mut lock,
 350            |keystroke, prefer_character_input| {
 351                PlatformInput::KeyDown(KeyDownEvent {
 352                    keystroke,
 353                    is_held: lparam.0 & (0x1 << 30) > 0,
 354                    prefer_character_input,
 355                })
 356            },
 357        ) else {
 358            return Some(1);
 359        };
 360        drop(lock);
 361
 362        let Some(mut func) = self.state.borrow_mut().callbacks.input.take() else {
 363            return Some(1);
 364        };
 365
 366        let handled = !func(input).propagate;
 367
 368        self.state.borrow_mut().callbacks.input = Some(func);
 369
 370        if handled { Some(0) } else { Some(1) }
 371    }
 372
 373    fn handle_keyup_msg(&self, wparam: WPARAM, lparam: LPARAM) -> Option<isize> {
 374        let mut lock = self.state.borrow_mut();
 375        let Some(input) = handle_key_event(wparam, lparam, &mut lock, |keystroke, _| {
 376            PlatformInput::KeyUp(KeyUpEvent { keystroke })
 377        }) else {
 378            return Some(1);
 379        };
 380
 381        let Some(mut func) = lock.callbacks.input.take() else {
 382            return Some(1);
 383        };
 384        drop(lock);
 385
 386        let handled = !func(input).propagate;
 387        self.state.borrow_mut().callbacks.input = Some(func);
 388
 389        if handled { Some(0) } else { Some(1) }
 390    }
 391
 392    fn handle_char_msg(&self, wparam: WPARAM) -> Option<isize> {
 393        let input = self.parse_char_message(wparam)?;
 394        self.with_input_handler(|input_handler| {
 395            input_handler.replace_text_in_range(None, &input);
 396        });
 397
 398        Some(0)
 399    }
 400
 401    fn handle_mouse_down_msg(
 402        &self,
 403        handle: HWND,
 404        button: MouseButton,
 405        lparam: LPARAM,
 406    ) -> Option<isize> {
 407        unsafe { SetCapture(handle) };
 408        let mut lock = self.state.borrow_mut();
 409        let Some(mut func) = lock.callbacks.input.take() else {
 410            return Some(1);
 411        };
 412        let x = lparam.signed_loword();
 413        let y = lparam.signed_hiword();
 414        let physical_point = point(DevicePixels(x as i32), DevicePixels(y as i32));
 415        let click_count = lock.click_state.update(button, physical_point);
 416        let scale_factor = lock.scale_factor;
 417        drop(lock);
 418
 419        let input = PlatformInput::MouseDown(MouseDownEvent {
 420            button,
 421            position: logical_point(x as f32, y as f32, scale_factor),
 422            modifiers: current_modifiers(),
 423            click_count,
 424            first_mouse: false,
 425        });
 426        let handled = !func(input).propagate;
 427        self.state.borrow_mut().callbacks.input = Some(func);
 428
 429        if handled { Some(0) } else { Some(1) }
 430    }
 431
 432    fn handle_mouse_up_msg(
 433        &self,
 434        _handle: HWND,
 435        button: MouseButton,
 436        lparam: LPARAM,
 437    ) -> Option<isize> {
 438        unsafe { ReleaseCapture().log_err() };
 439        let mut lock = self.state.borrow_mut();
 440        let Some(mut func) = lock.callbacks.input.take() else {
 441            return Some(1);
 442        };
 443        let x = lparam.signed_loword() as f32;
 444        let y = lparam.signed_hiword() as f32;
 445        let click_count = lock.click_state.current_count;
 446        let scale_factor = lock.scale_factor;
 447        drop(lock);
 448
 449        let input = PlatformInput::MouseUp(MouseUpEvent {
 450            button,
 451            position: logical_point(x, y, scale_factor),
 452            modifiers: current_modifiers(),
 453            click_count,
 454        });
 455        let handled = !func(input).propagate;
 456        self.state.borrow_mut().callbacks.input = Some(func);
 457
 458        if handled { Some(0) } else { Some(1) }
 459    }
 460
 461    fn handle_xbutton_msg(
 462        &self,
 463        handle: HWND,
 464        wparam: WPARAM,
 465        lparam: LPARAM,
 466        handler: impl Fn(&Self, HWND, MouseButton, LPARAM) -> Option<isize>,
 467    ) -> Option<isize> {
 468        let nav_dir = match wparam.hiword() {
 469            XBUTTON1 => NavigationDirection::Back,
 470            XBUTTON2 => NavigationDirection::Forward,
 471            _ => return Some(1),
 472        };
 473        handler(self, handle, MouseButton::Navigate(nav_dir), lparam)
 474    }
 475
 476    fn handle_mouse_wheel_msg(
 477        &self,
 478        handle: HWND,
 479        wparam: WPARAM,
 480        lparam: LPARAM,
 481    ) -> Option<isize> {
 482        let modifiers = current_modifiers();
 483        let mut lock = self.state.borrow_mut();
 484        let Some(mut func) = lock.callbacks.input.take() else {
 485            return Some(1);
 486        };
 487        let scale_factor = lock.scale_factor;
 488        let wheel_scroll_amount = match modifiers.shift {
 489            true => {
 490                self.system_settings()
 491                    .mouse_wheel_settings
 492                    .wheel_scroll_chars
 493            }
 494            false => {
 495                self.system_settings()
 496                    .mouse_wheel_settings
 497                    .wheel_scroll_lines
 498            }
 499        };
 500        drop(lock);
 501
 502        let wheel_distance =
 503            (wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_amount as f32;
 504        let mut cursor_point = POINT {
 505            x: lparam.signed_loword().into(),
 506            y: lparam.signed_hiword().into(),
 507        };
 508        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 509        let input = PlatformInput::ScrollWheel(ScrollWheelEvent {
 510            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 511            delta: ScrollDelta::Lines(match modifiers.shift {
 512                true => Point {
 513                    x: wheel_distance,
 514                    y: 0.0,
 515                },
 516                false => Point {
 517                    y: wheel_distance,
 518                    x: 0.0,
 519                },
 520            }),
 521            modifiers,
 522            touch_phase: TouchPhase::Moved,
 523        });
 524        let handled = !func(input).propagate;
 525        self.state.borrow_mut().callbacks.input = Some(func);
 526
 527        if handled { Some(0) } else { Some(1) }
 528    }
 529
 530    fn handle_mouse_horizontal_wheel_msg(
 531        &self,
 532        handle: HWND,
 533        wparam: WPARAM,
 534        lparam: LPARAM,
 535    ) -> Option<isize> {
 536        let mut lock = self.state.borrow_mut();
 537        let Some(mut func) = lock.callbacks.input.take() else {
 538            return Some(1);
 539        };
 540        let scale_factor = lock.scale_factor;
 541        let wheel_scroll_chars = self
 542            .system_settings()
 543            .mouse_wheel_settings
 544            .wheel_scroll_chars;
 545        drop(lock);
 546
 547        let wheel_distance =
 548            (-wparam.signed_hiword() as f32 / WHEEL_DELTA as f32) * wheel_scroll_chars as f32;
 549        let mut cursor_point = POINT {
 550            x: lparam.signed_loword().into(),
 551            y: lparam.signed_hiword().into(),
 552        };
 553        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 554        let event = PlatformInput::ScrollWheel(ScrollWheelEvent {
 555            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 556            delta: ScrollDelta::Lines(Point {
 557                x: wheel_distance,
 558                y: 0.0,
 559            }),
 560            modifiers: current_modifiers(),
 561            touch_phase: TouchPhase::Moved,
 562        });
 563        let handled = !func(event).propagate;
 564        self.state.borrow_mut().callbacks.input = Some(func);
 565
 566        if handled { Some(0) } else { Some(1) }
 567    }
 568
 569    fn retrieve_caret_position(&self) -> Option<POINT> {
 570        self.with_input_handler_and_scale_factor(|input_handler, scale_factor| {
 571            let caret_range = input_handler.selected_text_range(false)?;
 572            let caret_position = input_handler.bounds_for_range(caret_range.range)?;
 573            Some(POINT {
 574                // logical to physical
 575                x: (caret_position.origin.x.0 * scale_factor) as i32,
 576                y: (caret_position.origin.y.0 * scale_factor) as i32
 577                    + ((caret_position.size.height.0 * scale_factor) as i32 / 2),
 578            })
 579        })
 580    }
 581
 582    fn handle_ime_position(&self, handle: HWND) -> Option<isize> {
 583        unsafe {
 584            let ctx = ImmGetContext(handle);
 585
 586            let Some(caret_position) = self.retrieve_caret_position() else {
 587                return Some(0);
 588            };
 589            {
 590                let config = COMPOSITIONFORM {
 591                    dwStyle: CFS_POINT,
 592                    ptCurrentPos: caret_position,
 593                    ..Default::default()
 594                };
 595                ImmSetCompositionWindow(ctx, &config as _).ok().log_err();
 596            }
 597            {
 598                let config = CANDIDATEFORM {
 599                    dwStyle: CFS_CANDIDATEPOS,
 600                    ptCurrentPos: caret_position,
 601                    ..Default::default()
 602                };
 603                ImmSetCandidateWindow(ctx, &config as _).ok().log_err();
 604            }
 605            ImmReleaseContext(handle, ctx).ok().log_err();
 606            Some(0)
 607        }
 608    }
 609
 610    fn handle_ime_composition(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 611        let ctx = unsafe { ImmGetContext(handle) };
 612        let result = self.handle_ime_composition_inner(ctx, lparam);
 613        unsafe { ImmReleaseContext(handle, ctx).ok().log_err() };
 614        result
 615    }
 616
 617    fn handle_ime_composition_inner(&self, ctx: HIMC, lparam: LPARAM) -> Option<isize> {
 618        let lparam = lparam.0 as u32;
 619        if lparam == 0 {
 620            // Japanese IME may send this message with lparam = 0, which indicates that
 621            // there is no composition string.
 622            self.with_input_handler(|input_handler| {
 623                input_handler.replace_text_in_range(None, "");
 624            })?;
 625            Some(0)
 626        } else {
 627            if lparam & GCS_COMPSTR.0 > 0 {
 628                let comp_string = parse_ime_composition_string(ctx, GCS_COMPSTR)?;
 629                let caret_pos =
 630                    (!comp_string.is_empty() && lparam & GCS_CURSORPOS.0 > 0).then(|| {
 631                        let pos = retrieve_composition_cursor_position(ctx);
 632                        pos..pos
 633                    });
 634                self.with_input_handler(|input_handler| {
 635                    input_handler.replace_and_mark_text_in_range(None, &comp_string, caret_pos);
 636                })?;
 637            }
 638            if lparam & GCS_RESULTSTR.0 > 0 {
 639                let comp_result = parse_ime_composition_string(ctx, GCS_RESULTSTR)?;
 640                self.with_input_handler(|input_handler| {
 641                    input_handler.replace_text_in_range(None, &comp_result);
 642                })?;
 643                return Some(0);
 644            }
 645
 646            // currently, we don't care other stuff
 647            None
 648        }
 649    }
 650
 651    /// SEE: https://learn.microsoft.com/en-us/windows/win32/winmsg/wm-nccalcsize
 652    fn handle_calc_client_size(
 653        &self,
 654        handle: HWND,
 655        wparam: WPARAM,
 656        lparam: LPARAM,
 657    ) -> Option<isize> {
 658        if !self.hide_title_bar || self.state.borrow().is_fullscreen() || wparam.0 == 0 {
 659            return None;
 660        }
 661
 662        let is_maximized = self.state.borrow().is_maximized();
 663        let insets = get_client_area_insets(handle, is_maximized, self.windows_version);
 664        // wparam is TRUE so lparam points to an NCCALCSIZE_PARAMS structure
 665        let mut params = lparam.0 as *mut NCCALCSIZE_PARAMS;
 666        let mut requested_client_rect = unsafe { &mut ((*params).rgrc) };
 667
 668        requested_client_rect[0].left += insets.left;
 669        requested_client_rect[0].top += insets.top;
 670        requested_client_rect[0].right -= insets.right;
 671        requested_client_rect[0].bottom -= insets.bottom;
 672
 673        // Fix auto hide taskbar not showing. This solution is based on the approach
 674        // used by Chrome. However, it may result in one row of pixels being obscured
 675        // in our client area. But as Chrome says, "there seems to be no better solution."
 676        if is_maximized
 677            && let Some(ref taskbar_position) = self.system_settings().auto_hide_taskbar_position
 678        {
 679            // For the auto-hide taskbar, adjust in by 1 pixel on taskbar edge,
 680            // so the window isn't treated as a "fullscreen app", which would cause
 681            // the taskbar to disappear.
 682            match taskbar_position {
 683                AutoHideTaskbarPosition::Left => {
 684                    requested_client_rect[0].left += AUTO_HIDE_TASKBAR_THICKNESS_PX
 685                }
 686                AutoHideTaskbarPosition::Top => {
 687                    requested_client_rect[0].top += AUTO_HIDE_TASKBAR_THICKNESS_PX
 688                }
 689                AutoHideTaskbarPosition::Right => {
 690                    requested_client_rect[0].right -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 691                }
 692                AutoHideTaskbarPosition::Bottom => {
 693                    requested_client_rect[0].bottom -= AUTO_HIDE_TASKBAR_THICKNESS_PX
 694                }
 695            }
 696        }
 697
 698        Some(0)
 699    }
 700
 701    fn handle_activate_msg(self: &Rc<Self>, wparam: WPARAM) -> Option<isize> {
 702        let activated = wparam.loword() > 0;
 703        let this = self.clone();
 704        self.executor
 705            .spawn(async move {
 706                let mut lock = this.state.borrow_mut();
 707                if let Some(mut func) = lock.callbacks.active_status_change.take() {
 708                    drop(lock);
 709                    func(activated);
 710                    this.state.borrow_mut().callbacks.active_status_change = Some(func);
 711                }
 712            })
 713            .detach();
 714
 715        None
 716    }
 717
 718    fn handle_create_msg(&self, handle: HWND) -> Option<isize> {
 719        if self.hide_title_bar {
 720            notify_frame_changed(handle);
 721            Some(0)
 722        } else {
 723            None
 724        }
 725    }
 726
 727    fn handle_dpi_changed_msg(
 728        &self,
 729        handle: HWND,
 730        wparam: WPARAM,
 731        lparam: LPARAM,
 732    ) -> Option<isize> {
 733        let new_dpi = wparam.loword() as f32;
 734        let mut lock = self.state.borrow_mut();
 735        let is_maximized = lock.is_maximized();
 736        let new_scale_factor = new_dpi / USER_DEFAULT_SCREEN_DPI as f32;
 737        lock.scale_factor = new_scale_factor;
 738        lock.border_offset.update(handle).log_err();
 739        drop(lock);
 740
 741        let rect = unsafe { &*(lparam.0 as *const RECT) };
 742        let width = rect.right - rect.left;
 743        let height = rect.bottom - rect.top;
 744        // this will emit `WM_SIZE` and `WM_MOVE` right here
 745        // even before this function returns
 746        // the new size is handled in `WM_SIZE`
 747        unsafe {
 748            SetWindowPos(
 749                handle,
 750                None,
 751                rect.left,
 752                rect.top,
 753                width,
 754                height,
 755                SWP_NOZORDER | SWP_NOACTIVATE,
 756            )
 757            .context("unable to set window position after dpi has changed")
 758            .log_err();
 759        }
 760
 761        // When maximized, SetWindowPos doesn't send WM_SIZE, so we need to manually
 762        // update the size and call the resize callback
 763        if is_maximized {
 764            let device_size = size(DevicePixels(width), DevicePixels(height));
 765            self.handle_size_change(device_size, new_scale_factor, true);
 766        }
 767
 768        Some(0)
 769    }
 770
 771    /// The following conditions will trigger this event:
 772    /// 1. The monitor on which the window is located goes offline or changes resolution.
 773    /// 2. Another monitor goes offline, is plugged in, or changes resolution.
 774    ///
 775    /// In either case, the window will only receive information from the monitor on which
 776    /// it is located.
 777    ///
 778    /// For example, in the case of condition 2, where the monitor on which the window is
 779    /// located has actually changed nothing, it will still receive this event.
 780    fn handle_display_change_msg(&self, handle: HWND) -> Option<isize> {
 781        // NOTE:
 782        // Even the `lParam` holds the resolution of the screen, we just ignore it.
 783        // Because WM_DPICHANGED, WM_MOVE, WM_SIZE will come first, window reposition and resize
 784        // are handled there.
 785        // So we only care about if monitor is disconnected.
 786        let previous_monitor = self.state.borrow().display;
 787        if WindowsDisplay::is_connected(previous_monitor.handle) {
 788            // we are fine, other display changed
 789            return None;
 790        }
 791        // display disconnected
 792        // in this case, the OS will move our window to another monitor, and minimize it.
 793        // we deminimize the window and query the monitor after moving
 794        unsafe {
 795            let _ = ShowWindow(handle, SW_SHOWNORMAL);
 796        };
 797        let new_monitor = unsafe { MonitorFromWindow(handle, MONITOR_DEFAULTTONULL) };
 798        // all monitors disconnected
 799        if new_monitor.is_invalid() {
 800            log::error!("No monitor detected!");
 801            return None;
 802        }
 803        let new_display = WindowsDisplay::new_with_handle(new_monitor);
 804        self.state.borrow_mut().display = new_display;
 805        Some(0)
 806    }
 807
 808    fn handle_hit_test_msg(
 809        &self,
 810        handle: HWND,
 811        msg: u32,
 812        wparam: WPARAM,
 813        lparam: LPARAM,
 814    ) -> Option<isize> {
 815        if !self.is_movable || self.state.borrow().is_fullscreen() {
 816            return None;
 817        }
 818
 819        let mut lock = self.state.borrow_mut();
 820        if let Some(mut callback) = lock.callbacks.hit_test_window_control.take() {
 821            drop(lock);
 822            let area = callback();
 823            self.state.borrow_mut().callbacks.hit_test_window_control = Some(callback);
 824            if let Some(area) = area {
 825                return match area {
 826                    WindowControlArea::Drag => Some(HTCAPTION as _),
 827                    WindowControlArea::Close => Some(HTCLOSE as _),
 828                    WindowControlArea::Max => Some(HTMAXBUTTON as _),
 829                    WindowControlArea::Min => Some(HTMINBUTTON as _),
 830                };
 831            }
 832        } else {
 833            drop(lock);
 834        }
 835
 836        if !self.hide_title_bar {
 837            // If the OS draws the title bar, we don't need to handle hit test messages.
 838            return None;
 839        }
 840
 841        // default handler for resize areas
 842        let hit = unsafe { DefWindowProcW(handle, msg, wparam, lparam) };
 843        if matches!(
 844            hit.0 as u32,
 845            HTNOWHERE
 846                | HTRIGHT
 847                | HTLEFT
 848                | HTTOPLEFT
 849                | HTTOP
 850                | HTTOPRIGHT
 851                | HTBOTTOMRIGHT
 852                | HTBOTTOM
 853                | HTBOTTOMLEFT
 854        ) {
 855            return Some(hit.0);
 856        }
 857
 858        if self.state.borrow().is_fullscreen() {
 859            return Some(HTCLIENT as _);
 860        }
 861
 862        let dpi = unsafe { GetDpiForWindow(handle) };
 863        let frame_y = unsafe { GetSystemMetricsForDpi(SM_CYFRAME, dpi) };
 864
 865        let mut cursor_point = POINT {
 866            x: lparam.signed_loword().into(),
 867            y: lparam.signed_hiword().into(),
 868        };
 869        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 870        if !self.state.borrow().is_maximized() && cursor_point.y >= 0 && cursor_point.y <= frame_y {
 871            return Some(HTTOP as _);
 872        }
 873
 874        Some(HTCLIENT as _)
 875    }
 876
 877    fn handle_nc_mouse_move_msg(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
 878        self.start_tracking_mouse(handle, TME_LEAVE | TME_NONCLIENT);
 879
 880        let mut lock = self.state.borrow_mut();
 881        let mut func = lock.callbacks.input.take()?;
 882        let scale_factor = lock.scale_factor;
 883        drop(lock);
 884
 885        let mut cursor_point = POINT {
 886            x: lparam.signed_loword().into(),
 887            y: lparam.signed_hiword().into(),
 888        };
 889        unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 890        let input = PlatformInput::MouseMove(MouseMoveEvent {
 891            position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 892            pressed_button: None,
 893            modifiers: current_modifiers(),
 894        });
 895        let handled = !func(input).propagate;
 896        self.state.borrow_mut().callbacks.input = Some(func);
 897
 898        if handled { Some(0) } else { None }
 899    }
 900
 901    fn handle_nc_mouse_down_msg(
 902        &self,
 903        handle: HWND,
 904        button: MouseButton,
 905        wparam: WPARAM,
 906        lparam: LPARAM,
 907    ) -> Option<isize> {
 908        let mut lock = self.state.borrow_mut();
 909        if let Some(mut func) = lock.callbacks.input.take() {
 910            let scale_factor = lock.scale_factor;
 911            let mut cursor_point = POINT {
 912                x: lparam.signed_loword().into(),
 913                y: lparam.signed_hiword().into(),
 914            };
 915            unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 916            let physical_point = point(DevicePixels(cursor_point.x), DevicePixels(cursor_point.y));
 917            let click_count = lock.click_state.update(button, physical_point);
 918            drop(lock);
 919
 920            let input = PlatformInput::MouseDown(MouseDownEvent {
 921                button,
 922                position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 923                modifiers: current_modifiers(),
 924                click_count,
 925                first_mouse: false,
 926            });
 927            let result = func(input);
 928            let handled = !result.propagate || result.default_prevented;
 929            self.state.borrow_mut().callbacks.input = Some(func);
 930
 931            if handled {
 932                return Some(0);
 933            }
 934        } else {
 935            drop(lock);
 936        };
 937
 938        // Since these are handled in handle_nc_mouse_up_msg we must prevent the default window proc
 939        if button == MouseButton::Left {
 940            match wparam.0 as u32 {
 941                HTMINBUTTON => self.state.borrow_mut().nc_button_pressed = Some(HTMINBUTTON),
 942                HTMAXBUTTON => self.state.borrow_mut().nc_button_pressed = Some(HTMAXBUTTON),
 943                HTCLOSE => self.state.borrow_mut().nc_button_pressed = Some(HTCLOSE),
 944                _ => return None,
 945            };
 946            Some(0)
 947        } else {
 948            None
 949        }
 950    }
 951
 952    fn handle_nc_mouse_up_msg(
 953        &self,
 954        handle: HWND,
 955        button: MouseButton,
 956        wparam: WPARAM,
 957        lparam: LPARAM,
 958    ) -> Option<isize> {
 959        let mut lock = self.state.borrow_mut();
 960        if let Some(mut func) = lock.callbacks.input.take() {
 961            let scale_factor = lock.scale_factor;
 962            drop(lock);
 963
 964            let mut cursor_point = POINT {
 965                x: lparam.signed_loword().into(),
 966                y: lparam.signed_hiword().into(),
 967            };
 968            unsafe { ScreenToClient(handle, &mut cursor_point).ok().log_err() };
 969            let input = PlatformInput::MouseUp(MouseUpEvent {
 970                button,
 971                position: logical_point(cursor_point.x as f32, cursor_point.y as f32, scale_factor),
 972                modifiers: current_modifiers(),
 973                click_count: 1,
 974            });
 975            let handled = !func(input).propagate;
 976            self.state.borrow_mut().callbacks.input = Some(func);
 977
 978            if handled {
 979                return Some(0);
 980            }
 981        } else {
 982            drop(lock);
 983        }
 984
 985        let last_pressed = self.state.borrow_mut().nc_button_pressed.take();
 986        if button == MouseButton::Left
 987            && let Some(last_pressed) = last_pressed
 988        {
 989            let handled = match (wparam.0 as u32, last_pressed) {
 990                (HTMINBUTTON, HTMINBUTTON) => {
 991                    unsafe { ShowWindowAsync(handle, SW_MINIMIZE).ok().log_err() };
 992                    true
 993                }
 994                (HTMAXBUTTON, HTMAXBUTTON) => {
 995                    if self.state.borrow().is_maximized() {
 996                        unsafe { ShowWindowAsync(handle, SW_NORMAL).ok().log_err() };
 997                    } else {
 998                        unsafe { ShowWindowAsync(handle, SW_MAXIMIZE).ok().log_err() };
 999                    }
1000                    true
1001                }
1002                (HTCLOSE, HTCLOSE) => {
1003                    unsafe {
1004                        PostMessageW(Some(handle), WM_CLOSE, WPARAM::default(), LPARAM::default())
1005                            .log_err()
1006                    };
1007                    true
1008                }
1009                _ => false,
1010            };
1011            if handled {
1012                return Some(0);
1013            }
1014        }
1015
1016        None
1017    }
1018
1019    fn handle_cursor_changed(&self, lparam: LPARAM) -> Option<isize> {
1020        let mut state = self.state.borrow_mut();
1021        let had_cursor = state.current_cursor.is_some();
1022
1023        state.current_cursor = if lparam.0 == 0 {
1024            None
1025        } else {
1026            Some(HCURSOR(lparam.0 as _))
1027        };
1028
1029        if had_cursor != state.current_cursor.is_some() {
1030            unsafe { SetCursor(state.current_cursor) };
1031        }
1032
1033        Some(0)
1034    }
1035
1036    fn handle_set_cursor(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
1037        if unsafe { !IsWindowEnabled(handle).as_bool() }
1038            || matches!(
1039                lparam.loword() as u32,
1040                HTLEFT
1041                    | HTRIGHT
1042                    | HTTOP
1043                    | HTTOPLEFT
1044                    | HTTOPRIGHT
1045                    | HTBOTTOM
1046                    | HTBOTTOMLEFT
1047                    | HTBOTTOMRIGHT
1048            )
1049        {
1050            return None;
1051        }
1052        unsafe {
1053            SetCursor(self.state.borrow().current_cursor);
1054        };
1055        Some(1)
1056    }
1057
1058    fn handle_system_settings_changed(
1059        &self,
1060        handle: HWND,
1061        wparam: WPARAM,
1062        lparam: LPARAM,
1063    ) -> Option<isize> {
1064        if wparam.0 != 0 {
1065            let mut lock = self.state.borrow_mut();
1066            let display = lock.display;
1067            lock.click_state.system_update(wparam.0);
1068            lock.border_offset.update(handle).log_err();
1069            // system settings may emit a window message which wants to take the refcell lock, so drop it
1070            drop(lock);
1071            self.system_settings_mut().update(display, wparam.0);
1072        } else {
1073            self.handle_system_theme_changed(handle, lparam)?;
1074        };
1075        // Force to trigger WM_NCCALCSIZE event to ensure that we handle auto hide
1076        // taskbar correctly.
1077        notify_frame_changed(handle);
1078
1079        Some(0)
1080    }
1081
1082    fn handle_system_theme_changed(&self, handle: HWND, lparam: LPARAM) -> Option<isize> {
1083        // lParam is a pointer to a string that indicates the area containing the system parameter
1084        // that was changed.
1085        let parameter = PCWSTR::from_raw(lparam.0 as _);
1086        if unsafe { !parameter.is_null() && !parameter.is_empty() }
1087            && let Some(parameter_string) = unsafe { parameter.to_string() }.log_err()
1088        {
1089            log::info!("System settings changed: {}", parameter_string);
1090            if parameter_string.as_str() == "ImmersiveColorSet" {
1091                let new_appearance = system_appearance()
1092                    .context("unable to get system appearance when handling ImmersiveColorSet")
1093                    .log_err()?;
1094                let mut lock = self.state.borrow_mut();
1095                if new_appearance != lock.appearance {
1096                    lock.appearance = new_appearance;
1097                    let mut callback = lock.callbacks.appearance_changed.take()?;
1098                    drop(lock);
1099                    callback();
1100                    self.state.borrow_mut().callbacks.appearance_changed = Some(callback);
1101                    configure_dwm_dark_mode(handle, new_appearance);
1102                }
1103            }
1104        }
1105        Some(0)
1106    }
1107
1108    fn handle_input_language_changed(&self) -> Option<isize> {
1109        unsafe {
1110            PostMessageW(
1111                Some(self.platform_window_handle),
1112                WM_GPUI_KEYBOARD_LAYOUT_CHANGED,
1113                WPARAM(self.validation_number),
1114                LPARAM(0),
1115            )
1116            .log_err();
1117        }
1118        Some(0)
1119    }
1120
1121    fn handle_window_visibility_changed(&self, handle: HWND, wparam: WPARAM) -> Option<isize> {
1122        if wparam.0 == 1 {
1123            self.draw_window(handle, false);
1124        }
1125        None
1126    }
1127
1128    fn handle_device_lost(&self, lparam: LPARAM) -> Option<isize> {
1129        let mut lock = self.state.borrow_mut();
1130        let devices = lparam.0 as *const DirectXDevices;
1131        let devices = unsafe { &*devices };
1132        if let Err(err) = lock.renderer.handle_device_lost(&devices) {
1133            panic!("Device lost: {err}");
1134        }
1135        Some(0)
1136    }
1137
1138    #[inline]
1139    fn draw_window(&self, handle: HWND, force_render: bool) -> Option<isize> {
1140        let mut request_frame = self.state.borrow_mut().callbacks.request_frame.take()?;
1141        request_frame(RequestFrameOptions {
1142            require_presentation: false,
1143            force_render,
1144        });
1145        self.state.borrow_mut().callbacks.request_frame = Some(request_frame);
1146        unsafe { ValidateRect(Some(handle), None).ok().log_err() };
1147        Some(0)
1148    }
1149
1150    #[inline]
1151    fn parse_char_message(&self, wparam: WPARAM) -> Option<String> {
1152        let code_point = wparam.loword();
1153        let mut lock = self.state.borrow_mut();
1154        // https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-3/#G2630
1155        match code_point {
1156            0xD800..=0xDBFF => {
1157                // High surrogate, wait for low surrogate
1158                lock.pending_surrogate = Some(code_point);
1159                None
1160            }
1161            0xDC00..=0xDFFF => {
1162                if let Some(high_surrogate) = lock.pending_surrogate.take() {
1163                    // Low surrogate, combine with pending high surrogate
1164                    String::from_utf16(&[high_surrogate, code_point]).ok()
1165                } else {
1166                    // Invalid low surrogate without a preceding high surrogate
1167                    log::warn!(
1168                        "Received low surrogate without a preceding high surrogate: {code_point:x}"
1169                    );
1170                    None
1171                }
1172            }
1173            _ => {
1174                lock.pending_surrogate = None;
1175                char::from_u32(code_point as u32)
1176                    .filter(|c| !c.is_control())
1177                    .map(|c| c.to_string())
1178            }
1179        }
1180    }
1181
1182    fn start_tracking_mouse(&self, handle: HWND, flags: TRACKMOUSEEVENT_FLAGS) {
1183        let mut lock = self.state.borrow_mut();
1184        if !lock.hovered {
1185            lock.hovered = true;
1186            unsafe {
1187                TrackMouseEvent(&mut TRACKMOUSEEVENT {
1188                    cbSize: std::mem::size_of::<TRACKMOUSEEVENT>() as u32,
1189                    dwFlags: flags,
1190                    hwndTrack: handle,
1191                    dwHoverTime: HOVER_DEFAULT,
1192                })
1193                .log_err()
1194            };
1195            if let Some(mut callback) = lock.callbacks.hovered_status_change.take() {
1196                drop(lock);
1197                callback(true);
1198                self.state.borrow_mut().callbacks.hovered_status_change = Some(callback);
1199            }
1200        }
1201    }
1202
1203    fn with_input_handler<F, R>(&self, f: F) -> Option<R>
1204    where
1205        F: FnOnce(&mut PlatformInputHandler) -> R,
1206    {
1207        let mut input_handler = self.state.borrow_mut().input_handler.take()?;
1208        let result = f(&mut input_handler);
1209        self.state.borrow_mut().input_handler = Some(input_handler);
1210        Some(result)
1211    }
1212
1213    fn with_input_handler_and_scale_factor<F, R>(&self, f: F) -> Option<R>
1214    where
1215        F: FnOnce(&mut PlatformInputHandler, f32) -> Option<R>,
1216    {
1217        let mut lock = self.state.borrow_mut();
1218        let mut input_handler = lock.input_handler.take()?;
1219        let scale_factor = lock.scale_factor;
1220        drop(lock);
1221        let result = f(&mut input_handler, scale_factor);
1222        self.state.borrow_mut().input_handler = Some(input_handler);
1223        result
1224    }
1225}
1226
1227fn handle_key_event<F>(
1228    wparam: WPARAM,
1229    lparam: LPARAM,
1230    state: &mut WindowsWindowState,
1231    f: F,
1232) -> Option<PlatformInput>
1233where
1234    F: FnOnce(Keystroke, bool) -> PlatformInput,
1235{
1236    let virtual_key = VIRTUAL_KEY(wparam.loword());
1237    let modifiers = current_modifiers();
1238
1239    match virtual_key {
1240        VK_SHIFT | VK_CONTROL | VK_MENU | VK_LMENU | VK_RMENU | VK_LWIN | VK_RWIN => {
1241            if state
1242                .last_reported_modifiers
1243                .is_some_and(|prev_modifiers| prev_modifiers == modifiers)
1244            {
1245                return None;
1246            }
1247            state.last_reported_modifiers = Some(modifiers);
1248            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1249                modifiers,
1250                capslock: current_capslock(),
1251            }))
1252        }
1253        VK_PACKET => None,
1254        VK_CAPITAL => {
1255            let capslock = current_capslock();
1256            if state
1257                .last_reported_capslock
1258                .is_some_and(|prev_capslock| prev_capslock == capslock)
1259            {
1260                return None;
1261            }
1262            state.last_reported_capslock = Some(capslock);
1263            Some(PlatformInput::ModifiersChanged(ModifiersChangedEvent {
1264                modifiers,
1265                capslock,
1266            }))
1267        }
1268        vkey => {
1269            let keystroke = parse_normal_key(vkey, lparam, modifiers)?;
1270            Some(f(keystroke.0, keystroke.1))
1271        }
1272    }
1273}
1274
1275fn parse_immutable(vkey: VIRTUAL_KEY) -> Option<String> {
1276    Some(
1277        match vkey {
1278            VK_SPACE => "space",
1279            VK_BACK => "backspace",
1280            VK_RETURN => "enter",
1281            VK_TAB => "tab",
1282            VK_UP => "up",
1283            VK_DOWN => "down",
1284            VK_RIGHT => "right",
1285            VK_LEFT => "left",
1286            VK_HOME => "home",
1287            VK_END => "end",
1288            VK_PRIOR => "pageup",
1289            VK_NEXT => "pagedown",
1290            VK_BROWSER_BACK => "back",
1291            VK_BROWSER_FORWARD => "forward",
1292            VK_ESCAPE => "escape",
1293            VK_INSERT => "insert",
1294            VK_DELETE => "delete",
1295            VK_APPS => "menu",
1296            VK_F1 => "f1",
1297            VK_F2 => "f2",
1298            VK_F3 => "f3",
1299            VK_F4 => "f4",
1300            VK_F5 => "f5",
1301            VK_F6 => "f6",
1302            VK_F7 => "f7",
1303            VK_F8 => "f8",
1304            VK_F9 => "f9",
1305            VK_F10 => "f10",
1306            VK_F11 => "f11",
1307            VK_F12 => "f12",
1308            VK_F13 => "f13",
1309            VK_F14 => "f14",
1310            VK_F15 => "f15",
1311            VK_F16 => "f16",
1312            VK_F17 => "f17",
1313            VK_F18 => "f18",
1314            VK_F19 => "f19",
1315            VK_F20 => "f20",
1316            VK_F21 => "f21",
1317            VK_F22 => "f22",
1318            VK_F23 => "f23",
1319            VK_F24 => "f24",
1320            _ => return None,
1321        }
1322        .to_string(),
1323    )
1324}
1325
1326fn parse_normal_key(
1327    vkey: VIRTUAL_KEY,
1328    lparam: LPARAM,
1329    mut modifiers: Modifiers,
1330) -> Option<(Keystroke, bool)> {
1331    let (key_char, prefer_character_input) = process_key(vkey, lparam.hiword());
1332
1333    let key = parse_immutable(vkey).or_else(|| {
1334        let scan_code = lparam.hiword() & 0xFF;
1335        get_keystroke_key(vkey, scan_code as u32, &mut modifiers)
1336    })?;
1337
1338    Some((
1339        Keystroke {
1340            modifiers,
1341            key,
1342            key_char,
1343        },
1344        prefer_character_input,
1345    ))
1346}
1347
1348fn process_key(vkey: VIRTUAL_KEY, scan_code: u16) -> (Option<String>, bool) {
1349    let mut keyboard_state = [0u8; 256];
1350    unsafe {
1351        if GetKeyboardState(&mut keyboard_state).is_err() {
1352            return (None, false);
1353        }
1354    }
1355
1356    let mut buffer_c = [0u16; 8];
1357    let result_c = unsafe {
1358        ToUnicode(
1359            vkey.0 as u32,
1360            scan_code as u32,
1361            Some(&keyboard_state),
1362            &mut buffer_c,
1363            0x4,
1364        )
1365    };
1366
1367    if result_c == 0 {
1368        return (None, false);
1369    }
1370
1371    let c = &buffer_c[..result_c.unsigned_abs() as usize];
1372    let key_char = String::from_utf16(c)
1373        .ok()
1374        .filter(|s| !s.is_empty() && !s.chars().next().unwrap().is_control());
1375
1376    if result_c < 0 {
1377        return (key_char, true);
1378    }
1379
1380    if key_char.is_none() {
1381        return (None, false);
1382    }
1383
1384    // Workaround for some bug that makes the compiler think keyboard_state is still zeroed out
1385    let keyboard_state = std::hint::black_box(keyboard_state);
1386    let ctrl_down = (keyboard_state[VK_CONTROL.0 as usize] & 0x80) != 0;
1387    let alt_down = (keyboard_state[VK_MENU.0 as usize] & 0x80) != 0;
1388    let win_down = (keyboard_state[VK_LWIN.0 as usize] & 0x80) != 0
1389        || (keyboard_state[VK_RWIN.0 as usize] & 0x80) != 0;
1390
1391    let has_modifiers = ctrl_down || alt_down || win_down;
1392    if !has_modifiers {
1393        return (key_char, false);
1394    }
1395
1396    let mut state_no_modifiers = keyboard_state;
1397    state_no_modifiers[VK_CONTROL.0 as usize] = 0;
1398    state_no_modifiers[VK_LCONTROL.0 as usize] = 0;
1399    state_no_modifiers[VK_RCONTROL.0 as usize] = 0;
1400    state_no_modifiers[VK_MENU.0 as usize] = 0;
1401    state_no_modifiers[VK_LMENU.0 as usize] = 0;
1402    state_no_modifiers[VK_RMENU.0 as usize] = 0;
1403    state_no_modifiers[VK_LWIN.0 as usize] = 0;
1404    state_no_modifiers[VK_RWIN.0 as usize] = 0;
1405
1406    let mut buffer_c_no_modifiers = [0u16; 8];
1407    let result_c_no_modifiers = unsafe {
1408        ToUnicode(
1409            vkey.0 as u32,
1410            scan_code as u32,
1411            Some(&state_no_modifiers),
1412            &mut buffer_c_no_modifiers,
1413            0x4,
1414        )
1415    };
1416
1417    let c_no_modifiers = &buffer_c_no_modifiers[..result_c_no_modifiers.unsigned_abs() as usize];
1418    (
1419        key_char,
1420        result_c != result_c_no_modifiers || c != c_no_modifiers,
1421    )
1422}
1423
1424fn parse_ime_composition_string(ctx: HIMC, comp_type: IME_COMPOSITION_STRING) -> Option<String> {
1425    unsafe {
1426        let string_len = ImmGetCompositionStringW(ctx, comp_type, None, 0);
1427        if string_len >= 0 {
1428            let mut buffer = vec![0u8; string_len as usize + 2];
1429            ImmGetCompositionStringW(
1430                ctx,
1431                comp_type,
1432                Some(buffer.as_mut_ptr() as _),
1433                string_len as _,
1434            );
1435            let wstring = std::slice::from_raw_parts::<u16>(
1436                buffer.as_mut_ptr().cast::<u16>(),
1437                string_len as usize / 2,
1438            );
1439            Some(String::from_utf16_lossy(wstring))
1440        } else {
1441            None
1442        }
1443    }
1444}
1445
1446#[inline]
1447fn retrieve_composition_cursor_position(ctx: HIMC) -> usize {
1448    unsafe { ImmGetCompositionStringW(ctx, GCS_CURSORPOS, None, 0) as usize }
1449}
1450
1451#[inline]
1452fn is_virtual_key_pressed(vkey: VIRTUAL_KEY) -> bool {
1453    unsafe { GetKeyState(vkey.0 as i32) < 0 }
1454}
1455
1456#[inline]
1457pub(crate) fn current_modifiers() -> Modifiers {
1458    Modifiers {
1459        control: is_virtual_key_pressed(VK_CONTROL),
1460        alt: is_virtual_key_pressed(VK_MENU),
1461        shift: is_virtual_key_pressed(VK_SHIFT),
1462        platform: is_virtual_key_pressed(VK_LWIN) || is_virtual_key_pressed(VK_RWIN),
1463        function: false,
1464    }
1465}
1466
1467#[inline]
1468pub(crate) fn current_capslock() -> Capslock {
1469    let on = unsafe { GetKeyState(VK_CAPITAL.0 as i32) & 1 } > 0;
1470    Capslock { on }
1471}
1472
1473fn get_client_area_insets(
1474    handle: HWND,
1475    is_maximized: bool,
1476    windows_version: WindowsVersion,
1477) -> RECT {
1478    // For maximized windows, Windows outdents the window rect from the screen's client rect
1479    // by `frame_thickness` on each edge, meaning `insets` must contain `frame_thickness`
1480    // on all sides (including the top) to avoid the client area extending onto adjacent
1481    // monitors.
1482    //
1483    // For non-maximized windows, things become complicated:
1484    //
1485    // - On Windows 10
1486    // The top inset must be zero, since if there is any nonclient area, Windows will draw
1487    // a full native titlebar outside the client area. (This doesn't occur in the maximized
1488    // case.)
1489    //
1490    // - On Windows 11
1491    // The top inset is calculated using an empirical formula that I derived through various
1492    // tests. Without this, the top 1-2 rows of pixels in our window would be obscured.
1493    let dpi = unsafe { GetDpiForWindow(handle) };
1494    let frame_thickness = get_frame_thickness(dpi);
1495    let top_insets = if is_maximized {
1496        frame_thickness
1497    } else {
1498        match windows_version {
1499            WindowsVersion::Win10 => 0,
1500            WindowsVersion::Win11 => (dpi as f32 / USER_DEFAULT_SCREEN_DPI as f32).round() as i32,
1501        }
1502    };
1503    RECT {
1504        left: frame_thickness,
1505        top: top_insets,
1506        right: frame_thickness,
1507        bottom: frame_thickness,
1508    }
1509}
1510
1511// there is some additional non-visible space when talking about window
1512// borders on Windows:
1513// - SM_CXSIZEFRAME: The resize handle.
1514// - SM_CXPADDEDBORDER: Additional border space that isn't part of the resize handle.
1515fn get_frame_thickness(dpi: u32) -> i32 {
1516    let resize_frame_thickness = unsafe { GetSystemMetricsForDpi(SM_CXSIZEFRAME, dpi) };
1517    let padding_thickness = unsafe { GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi) };
1518    resize_frame_thickness + padding_thickness
1519}
1520
1521fn notify_frame_changed(handle: HWND) {
1522    unsafe {
1523        SetWindowPos(
1524            handle,
1525            None,
1526            0,
1527            0,
1528            0,
1529            0,
1530            SWP_FRAMECHANGED
1531                | SWP_NOACTIVATE
1532                | SWP_NOCOPYBITS
1533                | SWP_NOMOVE
1534                | SWP_NOOWNERZORDER
1535                | SWP_NOREPOSITION
1536                | SWP_NOSENDCHANGING
1537                | SWP_NOSIZE
1538                | SWP_NOZORDER,
1539        )
1540        .log_err();
1541    }
1542}